Zipper profiles with foamed sealant

ABSTRACT

A reclosable zipper is disclosed which includes a first profile which has a first compressible foamed sealant layer, and a first interlocking element, which is unfoamed, extending from the first profile. The zipper includes a second profile which has a second compressible foamed sealant layer, and a second interlocking element, which is unfoamed, extending from the second profile. The rigidity of the interlocking elements provides the required stability when the zipper is closed while the foamed sealant layers improve the sealing characteristics of the zipper to a packaging film.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationNo. 61/298,977, to Plourde, filed on Jan. 28, 2010, the disclose ofwhich is incorporated herein by reference in its entirety.

BACKGROUND OF THE DISCLOSED EMBODIMENTS

1. Field of the Disclosed Embodiments

The invention is directed to a reclosable zipper with zipper profilesthat comprise compressible foamed sealant layers for enhancing theconnection with packaging films, and wherein the zipper has interlockingelements which are unfoamed.

2. Description of the Related Art

Zippers are typically sealed to a packaging film by compressing thezipper, or a portion of the zipper, between layers of film by two heatedseal bars. For this system to work, the sealing surfaces and alignmentof the seal bars must be maintained to very tight tolerances, which areoften not the case in many packaging operations, resulting in weak orspotty seals.

One option is to enhance the connection between the reclosable zipperand the package film with a sealant. This is because sealants providestronger zipper to film seals at a lower temperature, pressure and/ordwell. However, typical relatively incompressible sealant layers resultin either weak spots in the seal or spots where seal bars burn throughthe packaging film, which results in weak spots in the package.

In view of the problems with typical sealants, a compressible foamedsealant layer is an option for enhancing the connection between thereclosable zipper and the package film. The compressibility of thefoamed sealant layer provides a more consistent zipper to package filmseal. For example, the durometer of the foamed sealant layer can beselected so that the foamed sealant layer collapses in areas of highspots when a seal bar presses against the zipper and packaging film,allowing the low spots in the seal bar to contact the zipper and filmwith adequate pressure to form a proper seal. In addition, maintenanceof a packaging machine is much less critical with a foamed sealantlayer. Another advantage is that foamed sealant layers act as insulatinglayers, reducing the likelihood that the inside surfaces of the zipperprofile flanges will seal to each other when the zipper is sealed to thepackage. In addition, there is a reduced likelihood that the flangeswill seal together where no intervening barrier is provided. Yet anotheradvantage of utilizing foamed sealant layers is that less plastic can beused to make the zipper, so that the zipper weighs less, improvingsustainability from a materials point as well as a shipping aspect.

An example of an application of foamed material for manufacturing azipper is provided in U.S. Pat. No. 5,520,463 to Tilman. Tilmandiscloses a zipper that is either completely foamed, or has a foamedcore encapsulated within a solid skin layer or casing of polymeric resinmaterial to which no blowing agent has been added. That is, in Tilman,the profiles, including the interlocking elements, are extruded from asynthetic polymeric resin material such as low-density polyethylene(LDPE). The resin material is mixed with a blowing agent, such asHYDROCEROL® CF 40 E, included in an amount less than or equal to 5% ofthe synthetic polymeric resin material by volume. The blowing agentprovides the resin with a fine-celled foam structure, increasing thesize (cross-sectional area) of the profiles without increasing the massof the zipper at opposing side seals. However, the foamed interlockingelements taught in Tilman fail to provide required rigidity. The lack ofrigidity of the interlocking elements of such zippers results inadequatestrength to remain closed when product is in the package.

BRIEF SUMMARY OF THE DISCLOSED EMBODIMENTS

A reclosable zipper is disclosed which includes a first profile whichcomprises a first compressible foamed sealant layer, and a firstinterlocking element, which is unfoamed, extending from the firstprofile. The zipper includes a second profile which comprises a secondcompressible foamed sealant layer, and a second interlocking element,which is unfoamed, extending from the second profile. The rigidity ofthe interlocking elements provides the required stability when thezipper is closed while the foamed sealant layers improve the sealingcharacteristics of the zipper to a packaging film.

BRIEF DESCRIPTION OF THE FIGURES

The accompanying figures illustrate the disclosed embodiments, which areto be considered as examples only, and in which:

FIG. 1 illustrates one embodiment of the disclosed zipper profiles withfoamed sealant layers and interlocking elements which are unfoamed;

FIG. 2 illustrates another embodiment of the disclosed zipper profileswith foamed sealant layers and interlocking elements which are unfoamed;

FIG. 3 illustrates yet another embodiment of the disclosed zipperprofiles with foamed sealant layers and interlocking elements which areunfoamed;

FIG. 4 illustrates a further embodiment of the disclosed zipper profileswith foamed sealant layers and interlocking elements which are unfoamed;

FIG. 5 illustrates a bag including yet a further embodiment of thedisclosed zipper profiles with foamed sealant layers and interlockingelements which are unfoamed; and

FIG. 6 illustrates an additional embodiment of the disclosed zipperprofiles with foamed sealant layers and interlocking elements which areunfoamed.

DETAILED DESCRIPTION OF THE DISCLOSED EMBODIMENTS

Turning to FIGS. 1-4, a reclosable zipper 10 is illustrated. The zipper10 includes a first profile 12 which comprises a first compressiblefoamed sealant layer 14, and a first interlocking element 16, which isunfoamed, that is, not foamed, extending from the first profile 12. Thezipper 10 includes a second profile 18 which comprises a secondcompressible foamed sealant layer 20, and a second interlocking element22, which is unfoamed, extending from the second profile 18. Therigidity of the interlocking elements 16, 22 provides the requiredstability when the zipper 10 is closed while the foamed sealant layers14, 20 improve the sealing characteristics of the zipper 10 to apackaging film for reasons noted above.

As illustrated in the figures, the first interlocking element 16 is afemale zipper element and the second interlocking element 22 is a malezipper element, and the first profile 12 is as large in a bagheight-wise direction as the second profile 18. The foamed sealantlayers 14, comprise the same foamed sealant. Specifically, for example,the foamed sealant layers 14, comprise a foamed polyofin sealant resin.Most polyolefin sealant resins can be foamed using commerciallyavailable foaming agents that react when heated in a barrel of anextruder. The interlocking elements 16, 22 comprise polyolefin sealantresin which is unfoamed. The resins used in the sealant layers mayinclude, but are not limited to mLLDPE, particularly mLLDPE's withdensities less than 0.910, co-polymers, and lower melting point resins.In addition, the sealant layer could be made from a similar resin as theinterlocking elements, only foamed.

The first profile 12 comprises a first product side flange 24, a firstconsumer side flange 26, and a first connecting flange 28 from which thefirst interlocking element 16 extends, where the first connecting flange28 is between, in a bag height-wise direction, the first product sideflange 24 and the first consumer side flange 26. The second profile 18comprises a second product side flange 30, a second consumer side flange32, and a second connecting flange 34 from which the second interlockingelement 22 extends, where the second connecting flange 34 is between, ina bag height-wise direction, the second product side flange 30 and thesecond consumer side flange 32.

In the embodiments illustrated in FIGS. 1 and 2, none of the flanges arefoamed. The first foamed sealant layer 14 is disposed on a first filmfacing side 36 of the first profile 12. The second foamed sealant layer20 is disposed on a second film facing side 38 of the second profile 18.

More specifically, in the embodiment illustrated in FIG. 1, the firstfoamed sealant layer 14 comprises a first product side foamed sealantsegment 40 on a first film facing side 42 of the first product sideflange 24, and a first consumer side foamed sealant segment 44 on afirst film facing side 46 of the first consumer side flange 26. Thesecond foamed sealant layer 20 comprises a second product side foamedsealant segment 48 on a second film facing side 50 of the second productside flange 30, and a second consumer side foamed sealant segment 52 ona second film facing side 54 of the second consumer side flange 32. Eachof the foamed sealant segments extends in the bag width-wise directionon respective profiles 12, 18.

In the embodiment illustrated in FIG. 2, the first foamed sealant layer14 comprises a first set of narrow-based foamed sealant ribs, including,for example, a first rib 56, a second rib 58 and a third rib 60, whichare substantially uniformly distributed in a bag height-wise directionacross the first film facing side 36 of the first profile 12. The secondfoamed sealant layer 20 comprises a second set of narrow-based foamedsealant ribs, including for example, a fourth rib 62, a fifth rib 64 anda sixth rib 66, which are substantially uniformly distributed in a bagheight-wise direction across the second film facing side 38 of thesecond profile 18. With such distribution, each flange includes at leastone foamed sealant rib. Each of the foamed sealant ribs extends in thebag width-wise direction on respective profiles 12, 18.

In the embodiment illustrated in FIG. 3, each flange is foamed.Accordingly, the first foamed sealant layer 14 comprises each of thefirst profile side flanges. The second foamed sealant layer 20 compriseseach of the second profile side flanges.

In the embodiment illustrated in FIG. 4, the first foamed sealant layer14 comprises the first product side flange 24 and the first consumerside flange 26, and the first connecting flange 28 is unfoamed. Thesecond foamed sealant layer 20 comprises the second product side flange30 and second consumer side flange 32, and the second connecting flange34 is unfoamed. The first connecting flange 28 is larger, in a bagheight-wise direction, than the second connecting flange 34. This isbecause the female interlocking element 16 has a base which is larger,in a bag height-wise direction, than the male interlocking element 22.

A bag is within the scope of the disclosed embodiments which comprisesany of the above disclosed reclosable zippers. As illustrated in FIG. 5,one embodiment for a bag 70 comprises a first bag panel 72 sealed to thefirst profile 12. The bag 70 also comprises a second bag panel 74 sealedto the second profile 18. The first and second bag panels 72, 74 may becontinuous or sealed at a bag bottom seal (not illustrated). The zipper10 illustrated in FIG. 5 is a slider type, where the first and secondprofiles 12, 18 including respective first and second product sideflanges 24, 30, along with respective first and second product sizefoamed sealant layers 40, 48. Instead of consumer side flanges, thezipper 10 includes a slider 76 which slides over the consumer side end78 of the zipper 10 to open or close the zipper 10.

As illustrated in FIG. 6, it is within the scope of the disclosedembodiments for the zipper 10 to be a flangeless, string zipper typemechanism. If the zipper 10 is flangeless, a first base 80 of the firstinterconnecting element 16 has a first foamed sealant layer 82 on afirst film facing side of the first base 80. On the other hand, a secondbase 84 of the second interconnecting element 22 has a second foamedsealant layer 86 on a second film facing side of the second base 84.

In sum, what has been disclosed is a zipper 10 for a reclosable packagewhich has compressible sealant layers 14, 20 for improving the sealingcharacteristics between the zipper 10 and packaging film. The foamedsealant layers 14, 20 can be localized, extruded as sealing ribs andextended in a bag width-wise direction across the backside of theprofiles 12, 18. Alternately the profile flanges can be entirely formedfrom a foamed sealant, or can be partially formed from a foamed sealantwith portions 28, 34 of respective profiles 12, 18, which supportrespective interlocking elements 16, 22, being left solid.

The present disclosed embodiments elements may be configured in otherspecific forms without departing from the spirit or essentialcharacteristics identified herein. The described embodiments are in allrespects only as illustrative and not as restrictive. The scope of theembodiments is, therefore, indicated by the appended claims and theircombination in whole or in part rather than by the foregoingdescription. All changes that come within the meaning and range ofequivalency of the claims are to be embraced within their scope.

1. A reclosable zipper comprising: a first profile which comprises afirst compressible foamed sealant layer, and a first interlockingelement, which is unfoamed, extending from the first profile; and asecond profile which comprises a second compressible foamed sealantlayer, and a second interlocking element, which is unfoamed, extendingfrom the second profile.
 2. The reclosable zipper of claim 1, whereinthe first interlocking element is a female zipper element and the secondinterlocking element is a male zipper element.
 3. The reclosable zipperof claim 1, wherein the foamed sealant layers comprise the same foamedsealant.
 4. The reclosable zipper of claim 1, wherein the foamed sealantlayers comprise a foamed polyofin sealant resin.
 5. The reclosablezipper of claim 1, wherein the interlocking elements comprise polyofinsealant resin which is unfoamed.
 6. The reclosable zipper of claim 3,wherein: the first profile comprises a first product side flange, afirst consumer side flange, and a first connecting flange from which thefirst interlocking element extends, where the first connecting flange isbetween, in a bag height-wise direction, the first product side flangeand the first consumer side flange; and the second profile comprises asecond product side flange, a second consumer side flange, and a secondconnecting flange from which the second interlocking element extends,where the second connecting flange is between, in a bag height-wisedirection, the second product side flange and the second consumer sideflange.
 7. The reclosable zipper of claim 6, wherein none of the flangesare foamed.
 8. The reclosable zipper of claim 7, wherein the firstfoamed sealant layer is disposed on a first film facing side of thefirst profile and the second foamed sealant layer is disposed on asecond film facing side of the second profile.
 9. The reclosable zipperof claim 7, wherein: the first foamed sealant layer comprises a firstproduct side foamed sealant segment on a first film facing side of thefirst product side flange, and a first consumer side foamed sealantsegment on a first film facing side of the first consumer side flange;and the second foamed sealant layer comprises a second product sidefoamed sealant segment on a second film facing side of the secondproduct side flange, and a second consumer side foamed sealant segmenton a second film facing side of the second consumer side flange.
 10. Thereclosable zipper of claim 9, wherein each of the foamed sealantsegments extends in the bag width-wise direction on respective profiles.11. The reclosable zipper of claim 8, wherein: the first foamed sealantlayer comprises a first set of narrow-based foamed sealant ribs that aresubstantially uniformly distributed in a bag height-wise directionacross the first film facing side of the first profile; and the secondfoamed sealant layer comprises a second set of narrow-based foamedsealant ribs that are substantially uniformly distributed in a bagheight-wise direction across the second film facing side of the secondprofile.
 12. The reclosable zipper of claim 11, wherein each flangeincludes at least one foamed sealant rib.
 13. The reclosable zipper ofclaim 12, wherein each of the foamed sealant ribs extends in the bagwidth-wise direction on respective profiles.
 14. The reclosable zipperof claim 6, wherein each flange is foamed, so that the first foamedsealant layer comprises each of the first profile side flanges and thesecond foamed sealant layer comprises each of the second profile sideflanges.
 15. The reclosable zipper of claim 6, wherein the first foamedsealant layer comprises the first product side flange and the firstconsumer side flange, and the first connecting flange is unfoamed, andthe second foamed sealant layer comprises the second product side flangeand second consumer side flange, and the second connecting flange isunfoamed.
 16. The reclosable zipper of claim 15, wherein the firstconnecting flange is larger, in a bag height-wise direction, than thesecond connecting flange.
 17. A bag comprising the reclosable zipper ofclaim 1 and further comprising a first panel sealed to the first profileand a second panel sealed to the second profile.
 18. The reclosablezipper of claim 1, wherein the zipper includes a slider.
 19. Thereclosable zipper of claim 1, wherein the zipper is flangeless.
 20. Thereclosable zipper of claim 19, wherein a first base of the firstinterconnecting element comprises said first foamed layer and a secondbase of the second interconnecting element comprises said second foamedlayer.